为了研究纹影系统的温度场定量测量技术, 本文详细阐述了纹影技术的定量测量原理, 并通过分析流场纹影图像灰度大小与未被遮挡的光源像面积的关系, 提出了一种新颖的流场温度定量测量的计算方法。首先, 在光学平台上搭建了透射式纹影系统, 将加热平台放置在该系统的测量区域, 利用CCD相机将采集到的纹影图像上传到上位机进行图像处理, 然后采用该算法计算得到温度场的测量值, 并与热电偶的测量值相对比。实验结果表明: 在室温20 ℃时, 将加热平台的温度分别设定为50 ℃和90 ℃, 纹影系统测量得到的温度值相对误差小于10%, 证明了该计算方法的可靠性, 实现了以纹影技术为基础的温度场定量测量。

In order to study temperature field measurement techniques of Schlieren systems, the principle of Schlieren quantitative measuring techniques is expounded. Based on the relationship between the grayness of a Schlieren image, along with the area of a light source, we propose an algorithm that is dependent on Schlieren to calculate flow field temperature. Firstly, a transmission Schlieren system is built on an optical platform and a hot plate is placed in the test area. Schlieren images are then captured by using a CCD camera, which are uploaded and stored on a computer for image processing. Finally, the algorithm is used to get the measured values of the temperature field, which then are compared with those by thermocouple measurement. The experimental results show that, when the temperature of the hot plate is set at 50 ℃ or 90 ℃, the relative errors of the flow field temperature measurement are less than 10%, the reliability of the algorithm is therefore proved and the quantitative measurement of temperature fields based on Schlieren techniques is realized.